Chapter 2: Research methods (GS) Flashcards
Describe hydrogen spinning with no external magnetic field.
Each hydrogen has a spin around own axis (spin creates its own small magnetic field)
Describe hydrogen spinning with spins in external magnetic field.
- External magnetic field causes spins to align in direction of magnetic field.
- Aligned H spins have own magnetic moment hidden under that of MRI
What is T1?
- Pens perpendicular
- Time for magnetic moment of spins to return to 63% of that of magnetic field of scanner
What is T2?
- Pens flip and spin ciruclar (and diaphase)
- time for magnetic moment of spins to lose 63% of magnetic moment (spins)
- hydrogens don’t spin together at same time
What is functional MRI?
- low contrast images taken in time with high spatial resolution
- BOLD signal
- ALS: measures blood flow in capillaries
What is structural MRI?
- image gives information about structure
- TOF: blood flow through brain
- susceptibility weight image: signal lower in veins caused by ion in hemoglobin
What can we do with T1?
- anatomical image of the brain
ventricles, white matter, gray matter
What can we do with diffusion?
- movement of water in the brain
visualize axon bundles and blood moving
What does BOLD stand for?
Blood, Oxygen, Level, Dependent, Signal
What does BOLD mean?
- to infer neuronal activity in the brain
- sensitive to changes in oxygen levels in venous blood flow
What is repetitive TMS?
- changes brain activity
- deactivate on area and produce a temporary lesion
What are the clinical uses of TMS? (4)
- depression
- drug abuse
- pain
- rehab after partial spinal cord injury
What is TMS?
Coil with current running through it. It is used to produce a magnetic pulse to stimulate region of interest
What is Transcranial?
Using an anode and cathode, we induce a currect in a region of interest
